py: Move to Python 3.4.0 compatibility.
Very little has changed. In Python 3.4 they removed the opcode STORE_LOCALS, but in Micro Python we only ever used this for CPython compatibility, so it was a trivial thing to remove. It also allowed to clean up some dead code (eg the 0xdeadbeef in class construction), and now class builders use 1 less stack word. Python 3.4.0 introduced the LOAD_CLASSDEREF opcode, which I have not yet understood. Still, all tests (apart from bytecode test) still pass. Bytecode tests needs some more attention, but they are not that important anymore.